All Clinical Trials for Ondansetron Hydrochloride Preservative Free

Hydroxyzine for the Prevention of Pruritus From Spinal Morphine in Transabdominal Hysterectomy Patients

Completed

Mahidol University

Phase 4

2007-08-01

Hydroxyzine is one of antihistamines that antagonizes H1 receptor, and it's effects are
reducing pruritus, nausea/vomiting, and the mild effect of sedation.With these effects
Hydroxyzine should be used in the prevention of these symptoms.

Intrathecal morphine provides good postoperative analgesia for up to 18-24 hour after
administration. Pruritus is the most common side effect of intrathecal morphine, which the
incidence was reported as 20%-100%2 and 63% in Songklanagarind Hospital. Pathophysiology of
opioid-induced pruritus remain unclear and more than one mechanism may be involved in the
development of opioid-induced pruritus, such as, mediated central µ opioid receptors,
Dopamine (D2) receptors, Serotonin (5-HT3) receptors, prostaglandin system, GABA receptors,
and glycine receptors, so that why opioid-induced pruritus is difficult to manage. Many
medications have been used to treat this side effect included antihistamines, 5-HT3
(serotonin) receptor antagonists, opioid antagonists, opioid agonist-antagonists, propofol,
and nonsteroidal antiinflammatory drugs.
Gabapentin is an anticonvulsant, a structural analog of aminobutyric acid, and currently
approved by the Food and Drug Administration for the treatment of partial seizures and
postherpetic neuralgia. Many studies have shown gabapentin to be effective in the case of
brachioradial pruritus, itch of neuropathic in origin, uremic pruritus, multiple
sclerosis-induced pruritus,cholestatic pruritus, itch produced by burn, and pruritus of
unknown origin. However, there is only one small study in Taiwan shown the effectiveness of
gabapentin 1200 mg in prevention of intrathecal morphine-induced pruritus in orthopedic
surgery, which could reduce incidence of pruritus from 77.5% to 47.5% (38.7% reduction).
Because gabapentin has several side effects especially in high dose such as drowsiness, dry
mouth, headache, unsteadiness, reduced co-ordination or slowed reaction, constipation,
diarrhea, peripheral edema, dizziness, confusion, loss of concentration, weight gain, and
nausea, vomiting, so in our study we decided to reduce the dose of gabapentin. Therefore, we
would like to know if gabapentin in a smaller dose (600 mg) used in the wider range of age
including the elderly can decrease the incidence of intrathecal morphine-induced pruritus in
orthopedic surgery in Songklanagarind Hospital.

The investigators hypothesize that given prophylactically, intravenous ondansetron will
attenuate the drop in blood pressure and heart rate frequently seen after spinal anesthesia.
Eighty-six American Society of Anesthesiologists (ASA) physical status I or II in
preoperative patient assessment, parturients age of 18 to 45 years scheduled to undergo
elective caesarean section will be enrolled.
Patients will be randomized to 2 groups: the ondansetron group, receiving 8 mg intravenous
ondansetron diluted in 10 mL of saline; or the placebo group, who were administered 10 mL of
saline given 5 minutes prior to performing the spinal anesthetic. Investigational Pharmacy
will randomize and dispense study drug.
Baseline measurements of vital signs will be taken. Otherwise standard management will then
be used:
- Patients must be NPO for 8 hours
- Pulse oximetry, EKG monitoring, noninvasive blood pressure at a minimum of every 3
minutes, more frequently if decided by the provider.
- Standard lumbar puncture in a sitting position the L3-L4 or L4-L5
- Whitacre pencil-point, 25 gauge
- Injectate: 2 mL of 0.75% hyperbaric bupivacaine, 100 mcg preservative free morphine, 20
mcg fentanyl
- Immediately after completing the subarachnoid injection, patients will be laid supine
with left lateral uterine displacement
The sensory level of anesthesia will be assessed in the standard fashion every five minutes
using ice. The motor component will tested using the Bromage scale for spinal anesthesia (0,
no paralysis; 1, inability to lift the thigh [only knee/feet]; 2, inability to flex the knee
[only feet]; 3, inability to move any joint in the legs).

Morphine, when given as part of spinal anesthesia, is associated high incidence of nausea
and pruritus, which may affect quality of recovery. The investigators hypothesize that
long-acting local anesthetic infusions via TAP catheter can provide better quality of
recovery after cesarean section than spinal morphine.

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